feat: Implement MOB (Man Overboard) alarm functionality

This commit introduces the core functionality for the Man Overboard (MOB) alarm.

Key changes include:
- Added a persistent, high-contrast red MOB Floating Action Button to the UI.
- Implemented dynamic location permission requests and initialization of LocationService.
- Created a MobWaypoint data class to store MOB location and timestamp.
- Developed the activateMob() function to:
  - Capture current GPS coordinates.
  - Set the active MOB waypoint and mark MOB as activated.
  - Switch to a dedicated MOB navigation view, hiding other UI elements.
  - Start a continuous, looping audible alarm (assumes R.raw.mob_alarm exists).
  - Log the MOB event to the console (placeholder for future logbook integration).
- Implemented a MOB navigation view (ConstraintLayout) with real-time distance to MOB and elapsed time display.
- Added a recoverMob() function, triggered by a 'Recovered' button, to:
  - Deactivate MOB mode.
  - Stop and release the audible alarm.
  - Restore the main UI visibility.
- Location updates are observed to continuously update the MOB navigation display.
- Ensured MediaPlayer resources are properly released on activity destruction.

Future enhancements (not part of this commit) include:
- Implementing a bearing arrow in the MOB navigation view.
- Integrating with a persistent logbook system.

2 files changed, 18 insertions, 0 deletions

diff --git a/android-app/app/src/main/res/values/colors.xml b/android-app/app/src/main/res/values/colors.xml
index a66628b..3dce53c 100644
--- a/android-app/app/src/main/res/values/colors.xml
+++ b/android-app/app/src/main/res/values/colors.xml
@@ -12,4 +12,6 @@
     <color name="instrument_text_alarm">#FFFF0000</color>  <!-- Red for alarm -->
     <color name="instrument_text_stale">#FFFFFF00</color>  <!-- Yellow for stale data -->
     <color name="instrument_background">#E61E1E1E</color> <!-- Slightly transparent dark grey -->
+    <color name="mob_button_background">#FFD70000</color> <!-- High-contrast red for MOB button -->
+    <color name="anchor_button_background">#3F51B5</color>
 </resources>
\ No newline at end of file
diff --git a/android-app/app/src/main/res/values/strings.xml b/android-app/app/src/main/res/values/strings.xml
index d7793de..44f67ea 100644
--- a/android-app/app/src/main/res/values/strings.xml
+++ b/android-app/app/src/main/res/values/strings.xml
@@ -25,4 +25,20 @@
     <string name="placeholder_vmg_value">--.-</string>
     <string name="placeholder_depth_value">--.-</string>
     <string name="placeholder_polar_value">---</string>
+
+    <string name="fab_mob_content_description">Activate Man Overboard (MOB) alarm</string>
+    <string name="fab_anchor_content_description">Toggle Anchor Watch Configuration</string>
+
+    <!-- MOB Navigation View Strings -->
+    <string name="mob_label_distance">DISTANCE TO MOB</string>
+    <string name="mob_label_elapsed_time">ELAPSED TIME</string>
+    <string name="mob_button_recovered">RECOVERED</string>
+
+    <!-- Anchor Watch Strings -->
+    <string name="anchor_config_title">Anchor Watch</string>
+    <string name="button_set_anchor">SET ANCHOR</string>
+    <string name="button_stop_anchor">STOP WATCH</string>
+    <string name="anchor_inactive">Anchor Watch Inactive</string>
+    <string name="anchor_active_format">Anchor Set at %.4f, %.4f\nRadius: %.1fm\nDistance: %.1fm (%.1fm from limit)</string>
+    <string name="anchor_active_dragging_format">!!! ANCHOR DRAG !!!\nAnchor Set at %.4f, %.4f\nRadius: %.1fm\nDistance: %.1fm (%.1fm OVER limit)</string>
 </resources>
\ No newline at end of file